Daniele Sechi

Extensive research has focused on the loess deposits in southern England, aiming to unravel their stratigraphic and palaeoenvironmental significance. However, no systematic mineral magnetic study on these deposits has yet been undertaken. Here we address this by investigating the magnetic mineral composition and alignment of loess at two sites in southern England, Lowland Point (LP) on the Lizard Peninsula of Cornwall, and Pegwell Bay (PB) in eastern Kent on the Isle of Thanet. A set of rock magnetic analyses was conducted to understand mineral magnetism within the studied sections. In addition, the primary depositional origin of the magnetic fabrics as well as their overprinting caused by various possible post‐depositional processes were examined through anisotropy of magnetic susceptibility (AMS). The magnetic mineral composition is similar at both sites, derived from both sedimentary (aeolian) and post‐depositional processes. The AMS results show magnetic foliation that varies between the two sites, aligning with the bedding plane, indicating deposition from gravitational dust fall at the PB site, and a stronger wind transport energy at the LP site. Although the magnetic lineation of bulk AMS is relatively weak, there is a noticeable tendency towards alignment in most samples, with flow directions from the SE indicated at both sections if a strong wind is assumed at LP, although with a possible SW direction if a weaker wind is assumed. These observations may imply the preservation of palaeowind directions during dust transport, with a substantial southerly component, which contradicts previous assertions of dominant northerly or northeasterly winds. Indeed, a possible dominant southeasterly wind direction between 25 and 18 ka would suggest a limited influence of katabatic, westerly or polar northeasterly winds during dust transport, and rather may imply the effect of low‐pressure systems passing through the English Channel during that period.

The relict beach deposit of the Cala Mosca marine terrace is considered an important section of Marine Isotopic Stage (MIS) 5e (ca. 125 ka) sea-level highstands. Analysis of the stratigraphy and sediments of the deposit indicates the presence of a composite marine terrace comprising two superimposed marine units, luminescence dated to the MIS 5e (137 ± 7, 134 ± 7 ka) and MIS 5c (92 ± 6 ka) substages. The stratigraphic superimposition of the two highstands, both placed ~5 m above present sea level, agrees with other areas along the Sardinia coasts. The evident superimposition of two sea-level highstands and development of the composite terrace cannot be accounted solely by high-frequency sea-level oscillation that occurred within MIS 5 for the Mediterranean Sea. This suggests controversial, but significant, regional versus local tectonic activity occurred during the Late Pleistocene.

The Alghero Bay is a coastal area of high economic value because of the presence of one of the most popular beaches of Sardinia (San Giovanni, Maria Pia, Le Bombarde, Lazzaretto). The organisms living in the meadow of Posidonia oceanica, which densely cover the offshore areas of the bay, represent the most important source of sediments to these beaches. For this reason, a detailed mapping of the local seabed features and distribution of P. oceanica constitutes an important tool for the coastal managing of the area. The integrated use of several methodologies, such as Side Scan Sonar, Remote Operating Vehicle, Drone and direct sediment sampling has allowed us to realize a very detailed seafloor map of the Alghero Bay.

The African fauna of the rare family of parasitoid wasps, Orussidae, is reviewed. Five genera with 24 valid species are recognized. Chalinus davidi Vilhelmsen n. sp. is described; the male of Chalinus albitibialis Vilhelmsen, 2005, the male of Leptorussus madagascarensis Vilhelmsen, 2007 and the female of Orussus smithi Blank et al., 2006 are described. A neotype is designated for Oryssus plumicornis Guérin-Meneville, [1849] to properly define the genus-group name Chalinus Konow, 1897. Chalinus braunsi (Enslin, 1911), C. orientalis Guiglia, 1937 and C. somalicus Guiglia, 1935 are regarded as new junior synonyms of C. plumicornis. Leptorussus kwazuluensis Vilhelmsen, 2003 is regarded as a new junior synonym of L. africanus Benson, 1955. Distribution records for specimens examined by us are listed. The Afrotropical component of the African orussid fauna shows a high degree of endemism, with two endemic genera and 13 endemic species; only Chalinus timnaensis Kraus, 1998 and Pseudoryssus niehuisorum Kraus, 1998 have a cross-Saharan distribution. In contrast, there are only three species of Orussidae occurring exclusively in North Africa. An additional six North African species also occur outside Africa, in adjacent parts of the Palaearctic. The Atlas Mountain range spanning Morocco, Algeria and Tunisia is a hotspot for orussid diversity, nine species having been recorded from there. The current Afrotropical assemblage of orussids are a result of several independently derived lineages, some possibly resulting from vicariance events dating as far back as the Late Cretaceous. The North African orussids have probably appeared as the result of several dispersal or speciation events, some putatively occurring as recently as the Pleistocene. Online Lucid interactive identification keys are available at: http://www.waspweb.org.

A multidisciplinary approach was followed to study the pedogenic and palaeoclimatic information preserved in a buried palaeosol belonging to a L ate Q uaternary succession located along the bay of A lghero ( n orth‐western S ardinia). The bay is dominated by a 5‐km long sandy beach‐ridge system backing an N‐S oriented lagoon system ( C alich). The succession studied is characterized by basal shallow marine deposits, followed by clayey lagoon sediments and colluvial strata and capped by a relatively thick aeolianite. The research was based on pedological and sedimentological analyses, supported by optically stimulated luminescence ( OSL ) dating and by an in‐depth micro‐morphological study. Three main climatic pulses were highlighted during the E emian. A wet period, with intense carbonate leaching occurred at the very beginning of the E emian interglacial followed by very dry climatic conditions. This dry phase was long and arid enough to allow the formation of a thick calcrete hardpan, a typical feature of semi‐arid environments. The hardpan is dated at about 120 ka (kilo annum) and this dry event is tentatively associated with the late E emian arid pulse ( LEAP ). The last phase of the E emian recorded the restoration of a wetter climate. Finally, the succession indicated that even in a cooler environment, the central M editerranean most probably maintained temperate conditions at least until the end of the MIS 5c (about 95 ka; early W ürm).